Dr. Timothy Cunningham, an epidemiologist based in Atlanta, Ga., was last seen on Feb. 12 when he left work early, saying he wasn’t feeling well.

More than a month has passed since a scientist employed by the Centers for Disease Control and Prevention mysteriously vanished, leaving friends and family increasingly desperate for answers about his whereabouts.

Dr. Timothy Cunningham, an epidemiologist based in Atlanta, Ga., was last seen on Feb. 12 when he left work early, saying he wasn’t feeling well.

Cunningham’s family reported him missing two days later, after they were unable to get in touch with him by phone or by text.

His parents drove through the night from their Maryland home and found no sign of their 35-year-old son in his apartment, but all of his known belongings were still there.

“It is not common in missing person’s cases to find someone’s entire belongings,” Atlanta Police Department Major Michael O’Connor said at a press conference last month.

“Tim never leaves Beau unattended,” his father, Terrell Cunningham, 60, told NBC at the time. “He just doesn’t do it.”

Atlanta police announced on March 6 the reward for information about Cunningham’s disappearance had been raised to $15,000.

Cunningham’s loved ones have also raised funds for a reward.

“Tim is a very loving, brilliant, and responsible young man,” a GoFundMe page reads. “Therefore, his sudden disappearance is highly irregular and very much out of character for him.”

The page has raised more than $24,000.

On Monday, the CDC appealed to Cunningham to return to those who love him, saying in a statement: “If Tim reads this message, we hope you come home soon.”

The agency also refuted reports that Cunningham had been passed over for a promotion in the days leading up to his disappearance.

“There has been news coverage that Commander Cunningham recently did not receive a promotion. As many of his colleagues in the USPHS have pointed out, this information is incorrect,” the CDC said. “In fact, he received an early promotion/exceptional proficiency promotion to Commander effective July 1, 2017, in recognition of his exemplary performance in the U.S. Public Health Service (USPHS).”

They continued: “Over and above any of his assignments at CDC, his early promotion within the USPHS reflects his excellence as an officer and an employee.”

The Atlanta Police Department said during a press conference not long after Cunningham was first reported missing that he had been passed over for a new position.

APD Sgt. John Chafee responded to the CDC’s statement that that information was incorrect, telling The Atlanta Journal-Constitution: “We stand behind every statement the Atlanta Police Department made about Dr. Cunningham’s employment, as our information came directly from the CDC. Any further questions about Dr. Cunningham’s employment, or this statement issued by the CDC today, would need to be answered by the CDC.”

Officials said there is no evidence of foul play, but it cannot be ruled out.

Anyone with information about Cunningham’s disappearance is asked to call 404-577-TIPS.